It will be. But be firm. You guys know what you need and that's each other. People mean well. But sometimes people are stupid.
Well, Rosie girl, there's no better way to help yourself feel better than by doing for others. See if you and your brothers who are close in age to you can help the younger ones have a not so empty Christmas. Try to do some of the things your Mom did. It will keep her memory alive in them as you talk about Christmases past, and maybe some of the 'misses' as well as the hits. It will also help take the pressure off your Dad.
Since my Dad died in 1981, the family has made sure that Mama spent Christmas Eve and Christmas Day with one of the siblings. My just younger sister always had her over on Christmas Eve, and she usually spent the night because my nephew was young and Mama liked seeing him on Christmas morning. The last few years, as that nephew got older, she still went there for Christmas Eve, but my older sister always had her over for Christmas Day.
Remember, if you need to vent, we're always here!